The principal objectives of the proposed research are to determine the ultrasonic propagation properties in intact tissue and to correlate these parameters to those obtained with the ultrasonic computer-assisted tomographic technique. Specifically, ultrasonic properties of attenuation, velocity and adsorption will be compared to the tissue constituents water, total protein and collagen with the view of determining the influence of such constituents upon ultrasonic propagation properties and, in turn, intercompare the values obtained with reconstruction techniques to determine the extent to which this technique yields accurate, quantitative attenuation, velocity and perhaps absorption data. Five measurement techniques will be employed to determine the spatial distribution of ultrasonic attenuation, velocity and absorption. They include a radiation force balance technique, the transient thermoelectric technique, a pulse time of flight technique, acoustic microscopy and ultrasonic computer-assisted tomographic technique.